High speed liquid food blenders most often utilize propeller-like blades to pulverize and otherwise mix the food being processed. In normal operation the food is circulated down to and past the blades for processing, and as long as the circulation pattern is consistent and uniform, efficient pulverization and mixing takes place.
However, particularly when mixing thicker, more viscous liquids, a channel of air is often formed extending from above the blades to the top of the blender, much as in a whirlpool effect. As the channel of air is drawn to the blades, an air bubble or dead air space is eventually formed around the blades which prohibits the food being processed from contacting the blades and thereby rendering the blades ineffective to mix the food. Presently, this can only be corrected by manually stirring the food to disperse the air pocket away from the blades. However, the air pocket will usually readily reappear thus making the blending process not only inefficient but also bothersome to the user.